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  <title>Test for correct handling of aStartStruct parameter to nsRuleNode::Compute*Data</title>
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  <script type="text/javascript" src="property_database.js"></script>
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<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=216456">Mozilla Bug 216456</a>
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  <span id="test"></span>
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<pre id="test">
<script class="testbody" type="text/javascript">

/**
 * The purpose of this test is to test that nsRuleNode::Compute*Data
 * functions are written correctly.  In particular, in these functions,
 * when the specified value of a property has unit eCSSUnit_Null,
 * touching the computed data is forbidden.  This is because we
 * sometimes stop walking up the rule tree when we find computed data
 * for an initial subsequence of our rules (i.e., an ancestor rule node)
 * that we can use as a starting point (aStartStruct) for the
 * computation for the current rule node.
 *
 * If one of these tests fails, you should look for a case where the
 * property's code in nsRuleNode::Compute*Data touches the computed
 * value when the specified value has eCSSUnit_Null, and fix it.
 *
 * The test works by maintaining one style rule that has every CSS
 * property specified, and a second style rule that has different values
 * for every property, an element that matches only the first rule (so
 * that we'll have a cached struct), and *later* an element that matches
 * both rules (for whose computation we'll find the struct cached from
 * the first element).  (It does this twice, once with the overriding in
 * each direction, because one of the cases might match the incorrect
 * overwriting.)  Then, in the second style rule, it unsets each
 * property, one at a time, and checks that the computation works
 * correctly.  (The reason to want every property set is to hit a case
 * where we can store the data in the rule tree... though this isn't
 * guaranteed.)
 */

function xfail_computecheck(prop, roundnum) {
    return false;
}

function xfail_test(prop, roundnum) {
    return false;
}

var gStyleSheet = document.getElementById("stylesheet").sheet;
var gRule1 = gStyleSheet.cssRules[gStyleSheet.insertRule("#base, #test {}", gStyleSheet.cssRules.length)];
var gRule2 = gStyleSheet.cssRules[gStyleSheet.insertRule("#test {}", gStyleSheet.cssRules.length)];

var gBase = getComputedStyle(document.getElementById("base"), "");
var gTest = getComputedStyle(document.getElementById("test"), "");

function round(lower_set, higher_set, roundnum) {

  for (var prop in gCSSProperties) {
    var info = gCSSProperties[prop];
    if (info.subproperties || info.get_computed)
      continue;
    gRule1.style.setProperty(prop, info[lower_set][0], "");
    gRule2.style.setProperty(prop, info[higher_set][0], "");
  }

  for (var prop in gCSSProperties) {
    var info = gCSSProperties[prop];
    if (info.subproperties || info.get_computed)
      continue;

    if ("prerequisites" in info) {
      for (var prereq in info.prerequisites) {
        gRule2.style.setProperty(prereq, info.prerequisites[prereq], "");
      }
    }

    gBase.getPropertyValue(prop);
    var higher_set_val = gTest.getPropertyValue(prop);
    gRule2.style.setProperty(prop, info[lower_set][0], "");
    var lower_set_val = gTest.getPropertyValue(prop);
    (xfail_computecheck(prop, roundnum) ? todo_isnot : isnot)(higher_set_val, lower_set_val, "initial and other values of " + prop + " are different");
    gRule2.style.removeProperty(prop);
    (xfail_test(prop, roundnum) ? todo_is : is)(gTest.getPropertyValue(prop), lower_set_val, prop + " is not touched when its value comes from aStartStruct");

    gRule2.style.setProperty(prop, info[higher_set][0], "");
    if ("prerequisites" in info) {
      for (var prereq in info.prerequisites) {
        gRule2.style.setProperty(prereq, gCSSProperties[prereq][higher_set][0], "");
      }
    }
  }
}

round("other_values", "initial_values", 1);
round("initial_values", "other_values", 2);

</script>
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